Telephone or like system



23, L J, MURRAY' v 2,387,525

TELEPHONE 0&1 LIKE SYSTEM 23,1945.l mim/mm 2.387.525..

TELEPHONE 0R LIKE SYSTEM `Filed June 2.- 1944 i 5 sheets-sheet z` FX1 v YL XN ,1

SIGNALLING slenALLmq A l l l/nc mamma, LgJ-[MURRAY' 381,525

. TELEPHONE on LIKE SYSTEM Filed Jung a, 1944 s sheets-snet s aber ` LAMPV RELAY Oct. 23, 1945.

L. J. MURRAY TELEPHONE OR LIKE SYSTEM Filed Jure 2, 1944 5 Sheets-Sheet 4 Oct. 23, 1945. L, J. MURRAY 2,387,525

` TELEPHONE 0R LIKE SYSTEM A Filed June 2,-1944 5 sheets-sheet 5 A ARI ARU1 H "mgm H" 1 A@ I/c` SIGNAL CCT.

- OIG SIGNAL, CCT` ALs @f can take place independently and simultaneously l in both directions.

therefore, the signals are composed of short pulses of frequency, and as there-is no danger of jamming these signals by speech or yIoy signals coming in the oppositedirection, there is 1` no necessity for them to be repeated.,v

Referring now to the circuit'operation of Figs.

2 and 3, when the operator plugs into the outgoing jack to originate a call, relay M operates over the sleeve circuit and brings upA relay MM. f 'l Relay MM at contacts MM2 causes switch TSO t step from its home position and it then continues to operate from earth over bank TSOI until it reaches position 6. During this movement relay FX is operated and at contacts FXI applies X frequency to theoutgoing signalling circuit. The wipers come tonrest in position 6 and relay FX releases to terminate the pulse which will have lasted for approximately 100 m; s. Relay CO is operated on the rstlstep of the `switch and at contacts CO2 energises relay FLS which causes the freel line 'signal lamps appropriate to the next idle multiple circuit to light, i l

AAt the distant incomingrelayset the pulse of X frequency operates-relay X in they Valve receiver VFRI and this relay at lcontacts VXI :operates relay L. Relay'L locks up at contacts LI and at contacts L2 operates relay N. This relay at-contacts NI in conjunction'with relay L operates the lamp relay-to light a lamp adjacent to the incoming jack to indicate to the operator that a call-has been initiated on this circuit.` Relay "N-also at contacts N2 prepares a'locking circuit for relay CR and at contacts-N3 opens lthe initial `circuit of relay-L and `preparesa circuit for relayCC.

WhenY thecincoming-operator answers the call by plugging intoY .the jack, relay S. is operated over the sleeve circuit to earth at contacts SSI :and relay SS is then energised. Relay SS at contactsSSI completes a locking circuit for itself and removes theshort-circuit from the lefthand windinglof diierential relaytDRat contacts SSZ opens a point ina circuit for relay .FYgat lcontacts SS3 connects up the. right-hand ing kel, the resistance in the sleeve circuit is Valteredand relay DR is sufficiently `unbalanced to `cause its operation. It thereupon at contacts DRI QL.v Contacts CLI then cause the switch TSI to step from-its home position andit then selfdrives from earth over bank VTSII to position I2. During the movementover contacts I--6 relay FY is operatedV and at contactsFYI connects up ya pulse of Y frequency to the outgoing signalling-circuit ,which pulse also has a duration of approximately 100m. si. y 4 Y l, AAt the outgoing relay set thegpulse of Y frequencyfoperates relay Y inthe valvehreceiver `VFCRO and contacts YI complete a`circuit for the upper winding of relay SO which accordingly operates. Relay SO at contacts SOI alters the resistance of the sleeve circuit to dim the supervisory lamp, at contacts SO2 prepares a circuit for relay SR whichjs at present short-circuited, at contacts SO3,-connects earthto :the-19th contactv in bank TSO5 andat'conta'tsSOd applies battery `to the ring conductor to repeat the sujgpervisory condition to the preceding circuits. At

the end ofhthe Y pulse relay Y releases and the short-circuit is removed from relay SR which operates inseriesvvith the lower winding of relay 3,01%!101 Vat contacts SRI re-arranges the circuits so that the next Ypulse'will maintain relay SR and short-circuitrelay SO, while at contacts SR2 the upper winding of relay SO is short-circuited.

4Vwinding of differential,relayDRwhich is not op- I energises relay TS whicl'iV in turn operates relay i,

When-the incoming operator restores the speaking' key after having received the details ofthe connection required, the resistance of the balance of relay DRwhich releases;l RelayiTS is accordingly released` followed'by` lrelay CL whereupon atcontacts CLI the vswitch TSI is again set in operation and" returns to itsjhome position, During .this movementv relayFY `is again operated over contacts ISQIS and a .pulse of Y frequencyis againv sent back over' the outgoing'signalling circuit. j f

At the outgoing relay set this/pulseof Y frequency a'gainoperates relay'Y which" shortcircuits relay S'Oand'zcausesgit 'to release, thereby at 'contacts SOI again bringing in the operators supervisory lamp. At the end of the Y pulse relay Y releases and permits relay SR to fall away so that'relays SO'andSR'are nowrestored to normal in readiness to respond to the next pair ofYpulses. Y

When' the connection hasbee'n completed to the calledjsubsc'riber by Veither manual or automatic means, h e is signalledin the usual manner 'and when he replies','battery is "connected back over thering conduct'orto operate relay TS over fits left-hand winding. Relay VTS as before opergoing operator answeringsuperyision.

The subscribers may nowv converse and when the called'subscriber clears, battery is removed from the Vring Vconductorv to releaserelay TS in the incoming relay set. ARelay CL accordingly falls away and a further, pulse ofv Y frequency 'is sentback while the switch TSI is moving to its home' position.' Thisfresultsrin the release 'of relays SO and SR andthe lighting of the outgoing operators supervisory, lamp,v

In'responseto this signalthe operator removes Lthe plug from Vthe jackV thereby releasing'relays M and MM. AtA contacts MM5 Abattery guarding potential is appliedlvto ,the sleeveo'f the jack until the equipmentis restored to'n'ormal and Vat contacts MMS earth isV applied tothe sixth contact in bank TSOI-to cause the switch to resume its movement. `It thereupon steps to position' 4'9 and during `this period relay FX is operated from the bank commoning to' cause two 100 in. s. pulses of X frequency to be applied tothe-,outgoing sig'- ynalling circuit, thesekpulsesbeing separated by a gap ctl00 m. s.v

AAt the incomingrelayfsetthe rstgpulsje of X frequency operates relay X. in the "valve ,receiver .VFRI and this causesoperation oferelay ACC.l This relay at contacts CCI peDmeSjacircuit for relay CR, at contacts CC2 short-circuits the left-hand 2,387,525 winding of relayDR 'and thus alters the resistance circuitfor relay CD. Relay CC has a-longer` hold periodithan 100 m. s. so that upon the receipt of thersecond X pulse relayrCR isoperated and locks upat contactsCRl. Relay CRalso at contacts CRZfopens another point in the circuit of relay CDatcontacts CR3 connects a further earth to thesleeve circuit `andat` contacts CR4 prepares aucircuit for relayl FY.

""Whenithe incoming `operator `notes from `the lighting Vof the `supervisory lamp" that the outgoing operatorhas clearedsheremoves the plug -Ifthe outgoingoperator wishes toash the distanti incomingoperator, `she depresses `the ringing key'whichcausesbattery to-be applied to the tip conductor and operates relay RR. Thereupon at contacts RR! `relay RA isenergised `and at contacts RR! -the switch TSO is caused to resume its steppingl* Relay RAl completes a locking circuit for itselfat contactsRA! and'at contacts RAZ alters the connection of `relay FX to the contacts offbanks TSO2-and TSO6. Since relayfMM is operated at this time, switch TSO will make a completerevolution and if the ringing `keyis still operated "will again pass contact `andmake a further revolution. During'this movement relay is operated for"approximatel`y 560 mus. and is released-for 440 m. s. so thai-,X pulses of this timing and spacing `are applied to the outgoing signalling circuit. `If theringing-key is released While theswitch TSO is in aninterm'ediate position,` relay RA1 is held operated inorder to ensure `that the signal is not mutilated. At the incoming -relay set the 560 mns. `X pulse operates relay CC *and when thepulseterminates relay CD is operated.` Relay CC however cannot hold up throughout the space period of 440 mi s. and consequently lno circuit is completed for relay CR on' the next pulse; The pulseisrepeated by contacts CCI-which alter the resistancein the sleeve circuit and thus bring about the hashing of the operatoris supervisory lamp. i r

\ "fIfi the incoming operator wishes to ilashthe outgoing operator, she Vthrows the `speaking key u `and then intermittently operates thevringing key whichiscommon to all thecord circuits. The operation of .thefspeaking key produces the eiects previously described, viz. the operation of relays DR, `TSland CL so that al m. Ys. pulse of Y frequencyis sent back over the signalling circuit. When `the ringing `keyis operated relay IRR energises and at contactsIRR! opens the circuit of relayzCL so that a further pulse of Y frequency is transmitted. t Theswitch TSIithus makes half a revolution each timethekey is operated or re-V leasedand `:therelays SO and SR respondes-prefrorrthe jack whereupon relays S and SS release r viously described so that the outgoirg operators supervisory lamp is flashed.

'Ihe arrangement shown in Figs. 4 and 5 for working into an automatic exchange operates in substantially the same manner with suitable modications to take care of the somewhat dii-Ierent conditions.

When the outgoing operator plugs into the jack AOG, relay AM operates overthe sleeve circuit and at contacts AM! energises relay AMM. This relay at contacts AMM! connects flicker earth to the sleeve circuit, at contacts AMM2 and AMM5 connects up relay ARR to the tip conductor, and

at contacts AMM3 applies earth to the P conduc tor extending-to the selector levels to guard the circuit from seizure over this means of access and energises relay ACZ by way of its lower winding.V Relay ACZ at contacts ACZ3 extends the earth from contacts AMM3 over the home position Contact of wiper ATSO3 to cause switch ATSO to step, whereupon relay AFX is operated and at contacts AFX2 provides a circuit to drive the switch to position 3. Relay AFX also at con tacts AFX! applies X frequency to the outgoing signalling circuit so that during the stepping of the switch and the slow release time of relay AFX a pulse of approximately m. s. duration is transmitted forward. Relay ACO is operated as soon as switch ATSO steps off-normal and at contacts ACO2 operates the lamp relay AFLS which causes the free line signal lamps appropriate to the next idle circuit to light while at contacts ACO3 relay ACZ is released.

At the incoming relay set at the distant ,exchange, the 100 m. s. pulse of X frequency operates relay X in the voice frequency receiver which then energizes relay AL. Relay AL at contacts ALI prepares a circuit for relay ARU, at contacts AL2 completes a locking circuit'for itself, at contacts `AL3 prepares a circuit for relay AAR, at contacts AL!! earths the P conductor extending to the associated incoming selector, at contacts ALB prepares a circuit for relay AC and at contacts ALG opens a point in the driving circuit for the switch ATSI. At the end of the X pulse contacts AX! operate relay AARwhich at contacts AAR! energises the line relay of the selector in series with relay AIL which also operates, and at. contacts AARZ energises relay ARU.` Contacts ARU! prevent the premature operation of relay ACR and `relay AIL energises relay ANwhich at contacts ANI supplements the earth on the P conductor, at contacts ANZ further prepares the circuit of relay AC and at contacts ANS prepares a locking circuit for relay AP.

When the outgoing operator throws the `dialling key, resistance battery is connected. to the tip conductor and operates relay ARR which at contacts ARR! energises relay AAM. This relay thereupon at contacts AAM! prepares the circuit for transmitting setting pulses of frequency and at contacts AAM2 energises relay AB. The latter relay at contacts ABI. further prepares the impulsing circuit, at contacts ABZ and` AB3 connects relay AMM to the tip and ring conductors, at contacts ABIL disconnects the flicker earth from the sleeve circuit and prepares a circuit for relay ALR, at contacts ABS releases relay ARR andat contacts ABB opens a point inthe driving circuit for switch ATSO. When the operator dials the wanted number relay AAM re@ sponds accordingly and at contacts AAM! repeats pulses of X frequency over the outgoing signal circuit, the line vbeing properly terminated during the make periods over the Voperated'contacts AAMI. l

At the incoming end the first pulse releases relay AAR which at contacts AARI repeats the pulse to the incoming selector. The operation of relay AX also energises relay AC which at contacts ACI short-circuits its left-handwinding to make itself slow to release, at contacts AC2 prepares a circuit for relay ACR and at contacts AC3 and AC4 provides an impedance-free impulsing circuit thereby releasing relay AIL. Relay AP is also operated and at contacts API locks `up to contacts AN3, at contacts APZ connects up relay AI to the positive conductor, at contact AP3 provides a further circuit for relay AN and at contacts AP4 closes another point in the circuit of relay ACR. The remaining impulses are repeated by relay AAR in similar manner and at the end of the train relay AC releases and again connects up relay AIL which re-opcrates. Further trains of impulses produce similar eiects to set up the automatic switch train and any tones which may be received during the setting up ofthe connection are transmitted back to the operator.

When the operator restores the dialling key, low resistance battery is connected to the sleeve circuit and brings about the operation of relay ALRyand after a short interval depending upon the release of certain relays in the position circuit, relay AAM also releases and brings down relay AB. Relay. ALR at contacts ALRI locks up, at contacts ALR2 opens the impulsing circuit to prevent the transmission of a further X pulse on the release of relay AAM, at contacts ALR3 prepares to connect battery to the ring conductor and at contacts ALR4 connects dicause the transmission of a further /100 m. vs.- pulse of Y frequency. 'I'his energises relayrAY, and at contacts AYI the lower winding of relay ACT is short-circuited while relay ACZ is held over its upper winding until the end of the pulse. The release of relay ACT causes the supervisory signal to be repeated to the operator andwhen she removes the plug from theV jack in response thereto, relays AM and AMM restore. The lat-V ter relay at contacts AMM3 provides a circuit to drive switch ATSO to position 23 and during this operation relay AFX is energised to apply a pulse of X frequency of approximately 400 m. s.

rect earth to the sleeve circuit to light the supererated and at contacts AFY l transmits a pulse of Y frequency of approximately 100 m. s. over the outgoing signalling circuit. Relay AY at the outgoing end responds to this pulse and energises relay ACT byl way of its upper winding. This relay at contacts ACTI disconnects direct earth from the sleeve circuit to dim the supervisory lamp, at contacts ACT2 short-circuits condenser AQA in the repeating coil bridge which has been in circuit to minimise distortion during dialling, at contacts ACTS prepares a locking' circuit for itself in series with the upper winding of relay ACZ and at contacts ACT connects through signalling battery to the ring conductor. At the end of the` Y pulse the short-circuit is removed from relays ACZ and ACT and the former now operates while the latter holds. Relay ACZ at contacts ACZI prepares a circuit for short-circuiting the lower winding of relay ACT and at contacts ACZ2 short-circuits the upper winding of this relay. Conversation may now proceed.

When the called party clears at Athe end of the conversation, battery is reversed back to normal so that relay AI releases and relay AIL again operates. The switch ATSI is then caused to advance'over the other half of its bank to duration to the outgoing signalling circuit. The

switch ATSO is then restored to its home posi-V tion over wiper ATSOZ which picks up half-second earth pulses over contacts 23 and 24 so Vas to maintain the circuit guarded during the release time of the equipment at the distant exchange.

At the distant end the effect of the long X pulse is to operate relay ACR which at contacts ACRI connects up relay AN to contacts AXI so as to be dependent upon the incoming pulse, at contacts ACRZ energises relay AC, at contacts ACR3 opens a point in the circuit of relay AL and at contacts ACR4 completes a locking circuit for itself. The operation of relay AC releasesV relay AAR which thereupon opens the outgoing circuit. When relay AX falls away at the end of the pulse, relay AN releases after its slow period and releases relays AP and AC. Relay ACR falls away on the release of relay AP and the circuit is then completely restored to normal. The release of relay AN disconnects earth from the P conductor to release the automatic switch train.

If a busy connection has been encountered, there will have been no reversal to bring about the release of relay AL and thecircuit conditions are therefore somewhat different. In these circumstances the operation of relay AX releases relay AAR and operates relay AC. Relay ARU is now released and a circuit is then completed for relay ACR over contacts APA, AC2 and ARUI. Relay ACR now disconnects relay AL and transfers the holding circuit for relay AN to contacts AXI and provides a holding circuit for relay AC. At the end of the X pulse, relay ANrfalls away and releases the remaining equipment as previously described. If the circuits are such that busy ash is returned, battery over the two speaking conductors operates both relays AIL and AI and causes the release of relay AL but in these circumstances there is no circuit for setting the switch ATSI in operation so that a false answer signal is not transmitted.

The case will now be briefly considered in which the circuit is taken into use from the levels of automatic switches rather than from an operators position. In this case when the circuit is seized relay AA is operated over the speaking conductors and operates relay AB. Thereupon at contacts ABG earth is applied to the P conductor to hold the preceding train of switches and to maintain relay ACZ which was energised by the earth originally fed forward. Relay ACZ` causes a seizing pulse of X frequency of m. s. duration to be transmitted to the distant exchange in the manner previously described whereupon the equipment thereat is prepared in the usual manner. The operation of relay ACO when the switch ATSO moves off normal connects guarding battery to the sleeve of the jack to indicate to the operator that the circuit is busy, Incoming trains of impulses are received on relay VAAwhich at Contact AAI repeats'them v fthe preceding switches.

"2,387,525 jinlth'ei dorm'. ori xlplses over the "outgoing signalngcf' uit; ilDuring fthe lsettingup of the con- 1hectareniany` tones which may beencounteredare -itmnsmi'tt'ediback lover contacts and AMMS `since Urelay AMM is` not `operated under these 1 when the cauedfsubscriber "answers, me 10o jm. spulse 'of Yirequency brings `about the operationifofrelay `ACTg1as before` and "this relay at con-- `tactsACTS and ACTS r'e'ver'ses `battery over the Tweaking-"conductors to repeat the supervision i to Whenthe called subscrlber clears;.the ltransmission of` the further ACT which reverseslbattery back .'to` normal and thus repeats the supervisory signal to the preced- -ing train fof, switches;` When the calling party releases; the loopfcircuitr'for relay AA is opened ,fandwit'fallsjaway `thereby `bringing "down relay 'il This at contacts ABB completes a driving 5to-:contact 23ztofeiecttheltransmission of a 400 avclearingupulse overthe signalling circuit. Thiseffects th'ez-lrelea'setof` lthe :equipment at the l incoming-end in the manner `previously described.

lengthlover one` of thefassociated sub-channels to the outgoing end of said line to indicate the reply of the called party in a connection extend- "ed over the corresponding speech channel, first self-locking means at the outgoing end responsive to said signal, means fortransmitting a single signalof predetermined voice frequency and of predetermined length over one of the associated sub-channels to the outgoing end of said line to indicate the clearing of the called party andsecond self-locking means at the outgoing end responsive to said signal to give a clearing indication.

2. A telephone system including in combination a transmission line, means for dividing said line into a plurality of speech channels and a single signalling channel, means for dividing said signalling channel into a number of sub-channels individual to each of said speech channels, means individually associated with each of said speech channels for transmitting a single signal of predetermined voice frequency and of predetermined length over one of the associated sub-channels tothe outgoing end of said line to indicate the reply of the called party in a connection extended over the `corresponding speech channel, rst self-locking means at the outgoing end responsive to said signal, means for transmitting a single signal of the same predetermined voice frefequ'alftoftwice the number 1vof said speech channels," tvvo of said sub-channels being individually associated witheach of said speech channels,

Y means individually associated With each of said speech channels for transmitting signals of predetermined voice frequency over one of said fassociated sub-channels fromthe outgoing end f circuiti for the. switchl ATSO 'which `then rotates of said line to `control the settng up of a connection, means individually associated with each 'of said speech channels for transmitting a single `'signal of predetermined voice frequency and of predetermined length over the other ofsaid associated sub-channels `to the outgoing end of said `line to indicate the reply of the called party in a "connection extended over the corresponding speech channel, l'lrstself-locking means at the outgoing 'end responsive to said signal, means for party and -second self-locking means at the `outgoing "end responsive to said 'signal to give '-a clearing indication; Y

4. A telephone system including in combinationa transmission line, means for dividing said line into a plurality of speech channels and a single signalling channel, vmeans for dividing said signalling channel into a number of subchannels equal to twice the number of said speech channels, two vof 'said sub-channels being individually-associated with each of said speech channels, means individually associated with each of l'said speech channels for transmitting signals of a iirst predetermined voice frequency over one of said associated sub-channels from the outgoing end of said line to control the setting up of a connection,.me`ansindividually associated with each of said speech channels for transmitting a single signal of a second predetermined voice frequency and of predetermined length over the other of said associated sub-channels to the outgoing end of said line to indicate the reply of the called party in a connection extended over the corresponding speech channel, rst self-locking means at theA outgoing end responsive to said signal, means for transmitting a single signal of said second predetermined voice frequency and of predetermined length over said other associated sub-channel to the outgoing end of said line to indicate the y said speech channels, means individuallyI associated with each of said speech channels for transmitting a single signal of predetermined voice frequency and of predetermined length over one of said associated sub-channels to the outgoing end of said line to indicate the reply of the called party in a connection extended over the corresponding speech channel, rst self-locking means at the 'outgoing end of each speech channel responsive to said signal, means for transmitting a single signal of the same predetermined -frequency and length over the same sub-channel to the outgoing end of said line to indicate the clearing of the called party, and second self- Van f electromagnetically-operated rotary switch arranged to operate by self-interlocking `means'individually associated with each speech channel and responsive to said signal to give a, clearing indication.

6. A telephone system according to claim 4 in which timing of the predetermined length of said signals is eiected by the stepping operation of step-by-step ruption.

7. A telephone system including in combina- Htion a transmission line, means for dividing said line into a plurality of carrier speech channels and a single carrier signalling channel, means `for dividing said signalling channel into a number of sub-channels equal to twice the number of -said speech channels, two of said sub-channels being individually associated with each of said speech channels, means individually associated with each of said speech channels for transmitting a single signal of predetermined voice frequency and of predetermined length over one of said associated sub-channels to the outgoing end of said line to indicate the reply of the called party in a connection extended over the corresponding speech channel, a relay individually 4associated with each speech channel and arto de-energize on the termination of said second signal;

8. A telephone system including in combina.- tion a transmission line, means for dividing'said line into a plurality of carrier speech channels and a single carrier signalling channel, means for dividing said signalling channel into a number of sub-channels equal to twice theznumber of said speech channels, two of said sub-channels being individually associated With each of said speech channels, an operators position at the outgoing end of said line, means for extending a connection from said operators position over one of said speech channels toa second operators position at the incoming end of said line, means for transmitting a single signal of predetermined voice frequency and of predeter'4 mined length over the appropriate oneof said associated sub-channels on the reply of said second operator, self-locking means responsive to said signal to give a supervisory indication, means for transmitting a single signal of the same predetermined frequency and length over said signalling sub-channel on the Withdrawal of said second operator, means responsive to said signal to unlock said self-locking means Aand cancel said supervisory indication, means for extending a connection from said second operators position of a called party, means for transmitting a single signal of the same predetermined frequency and length over said signalling subchannel on the reply of said called party to re.

operate said self-locking means and means for transmitting a single signal of thesame predetermined frequency and length over said sub-channel on the clearing of the called party to again unlock said self-locking means.

LAWRENCE JOHN MURRAY. 

